Stress slows hair growth and scientists have determined why

There's the old saying that worry and stress makes you feel like "pulling your hair out." (Of course, there's also the OCD-spectrum hair-pulling disorder called Trichotillomania, often triggered by stress.) Now, scientists have identified a stress hormone that appears to inhibit hair growth. In studies on mice, they determined that the stress protein, corticosterone inhibits a protein called growth arrest-specific 6 (GAS6) which is responsible for activating the hair growth process. From Nature:

[Harvard biologist Sekyu] Choi and colleagues first tested the role of adrenal glands — which produce stress hormones and constitute a key endocrine organ — in the regulation of hair growth, by surgically removing them from mice. Telogen phases were much shorter in the hair follicles of these animals (which the team dubbed ADX mice) than in control mice (less than 20 days compared with 60–100 days), and the follicles engaged in hair growth roughly three times as often. The authors were able to suppress this frequent hair growth and restore the normal hair cycle by feeding the ADX mice corticosterone (a stress hormone normally produced by the animals' adrenal glands). Interestingly, when they unpredictably applied various mild stressors to normal mice for nine weeks, they observed elevated corticosterone levels accompanied by reduced hair growth, supporting the idea that corticosterone produced by the adrenal glands during chronic stress inhibits the initiation of hair growth[…]

Delivering GAS6 into the skin using an adenovirus vector (a common tool in gene therapy) not only stimulated hair growth in normal mice, but also restored hair growth during chronic stress or corticosterone feeding[…]

Modern life for humans is inevitably stressful. But perhaps, one day, it will prove possible to combat the negative impact of chronic stress on our hair, at least — by adding some GAS6.